Coating compositions comprising a polyisocyanate compound, a hydroxyl-functional film forming polymer, and a non volatile branched monoalcohol

ABSTRACT

The current invention relates to a coating composition comprising a polyisocyanate compound, a hydroxyl-functional film-forming polymer, and a non-volatile branched monoalcohol. An aliphatic branched monoalcohol is preferred. More preferred are long chain non-volatile branched monoalcohols. This results in coating compositions that have improved flow behavior and that produce coatings having improved appearance without an adverse effect on other properties. 
     The invention also relates to a multi-component coating composition. Preferably, the multi-component coating composition is a two-component coating composition comprising a polyisocyanate component and a hydroxyl-functional component, wherein the hydroxyl-functional component, in addition to the hydroxyl-functional film forming polymer also comprises the non-volatile branched monoalcohol. The non-volatile branched monoalcohol can be mixed with the hydroxyl-functional film forming polymer or can be added during the preparation of the hydroxyl functional film forming polymer. 
     Finally, the present invention relates to the use of the coating compositions in the refinish industry, in particular the body shop, to repair automobiles and transportation vehicles and in finishing large transportation vehicles such as trains, trucks, buses, and airplanes, and to a process for the preparation of a multilayer coating comprising the steps of applying a basecoat composition on an optionally coated substrate, optionally curing the basecoat, applying on top of the basecoat a clearcoat composition according to the present invention, and curing the multilayer coating.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of Provisional Application No.60/224139, filed on Aug. 10, 2000 and European patent application No. EP00203453.6, filed on Sep. 28, 2000.

BACKGROUND OF THE INVENTION

There is an industry need to improve the flow behavior of coatingcompositions comprising polyisocyanate compounds and hydroxyl-functionalfilm-forming polymers, and the appearance of coatings formed from suchcoating compositions while maintaining other properties of the coatingcompositions and coatings. It has been found that non-volatile branchedmonoalcohols can provide the desired improvements. Particularly usefulare long chain linear monoalcohols with 12 or more carbon atoms. Sincethese monoalcohols with 12 or more carbon atoms are generally solid atambient temperature, their use in coatings compositions, is thought tobe limited. Surprisingly, it has been found that some long chainnon-volatile branched monoalcohols are suitable as an additive incoating compositions, in particular multi-component (at least twocomponent) coating compositions. This results in coating compositionsthat have improved flow behavior and that produce coatings havingimproved appearance without an unacceptably adverse effect on otherproperties.

Coating compositions comprising a polyisocyanate and polyol are knownfrom, for example, European Patent Application No. 0 219 131. Thisreference also discloses use of such coating compositions for variouspurposes, including the top coating of relatively heavy weight articles,such as vehicles, industrial machinery and building and constructionmachinery.

Fast setting, fast curing coating compositions using acrylic binderswith a high Tg are mentioned, for example, in U.S. Pat. Nos. 5,741,880and 5,759,631. The combination of a hard acrylic with a low viscositypolyol is mentioned in U.S. Pat. No. 5,286,782. To obtain low VOCcoating compositions, fast evaporating solvents with low photochemicalreactive solvents such as acetone, methylacetate and tertiarybutylacetate can be added. Combining fast evaporating solvents withacrylic binders can result in poor flow and appearance. To improve flowand appearance, large amounts of low viscosity polyols are sometimesadded, but they may cause slower curing and poor setting.

U.S. Pat. No. 4,235,766 discloses a coating composition comprising anorganic polyhydroxy compound and an organic polyisocyanate. The coatingcomposition additionally comprises 2-methyl-2-propanol and/or2-methyl-2-butanol. These monoalcohols are volatile compounds. Adisadvantage in using volatile compounds is that there is no control inhow much of the compound is built into the coating after application ofthe coating composition and how much evaporates and contributes to theVOC of the coating composition.

SUMMARY OF THE INVENTION

The current invention relates to a coating composition comprising apolyisocyanate compound, a hydroxyl-functional film-forming polymer, anda nonvolatile branched monoalcohol. An aliphatic branched monoalcohol ispreferred.

The invention also relates to a multi-component coating composition.Preferably, the multi-component coating composition is a two-componentcoating composition comprising a polyisocyanate component and ahydroxyl-functional component, wherein the hydroxyl-functionalcomponent, in addition to the hydroxyl-functional film forming polymeralso comprises the non-volatile branched monoalcohol. The non-volatilebranched monoalcohol can be mixed with the hydroxyl-functional filmforming polymer or can be added during the preparation of the hydroxylfunctional film forming polymer.

DETAILED DESCRIPTION OF THE INVENTION

Any non-volatile branched aliphatic monoalcohol may be used in thecurrent invention. Nonvolatile branched aliphatic monoalcohol preferablyused in the current invention has at least 12 carbon atoms, morepreferably at least 16 carbon atoms. Also a mixture of non-volatilebranched monoalcohols with at least an average of 12 carbon atoms can beused, more preferably at least an average of 16 carbon atoms.Preferably, a Guerbet alcohol or Guerbet alcohol mixture is used, morepreferably a Guerbet alcohol with at least 12 carbon atoms (or a mixtureof Guerbet alcohols with at least an average of 12 carbon atoms), mostpreferably at least 16 carbon atoms (or a mixture of Guerbet alcoholswith at least an average of 16 carbons). Guerbet alcohols are branched,primary alcohols that are linear, have two carbon chains and the branchpoint is always at the second carbon position.

The hydroxyl-functional film forming polymer has preferably a hydroxyvalue between 50 and 300 mg KOH/g based on solids, more preferablybetween 70 and 200 mg KOH/g. The number average molecular weight of thepolymer is preferably lower than 6000 as measured by gel permeationchromatography with polystyrene as standard, more preferably less than4500. The degree of molecular dispersion, i.e., the ratio of Mw to Mn,preferably is in the range of 1.1 to 5, the range from 1.1 to 3 beingparticularly preferred. The acid value of the polymer preferably isbetween 0 and 50 mg KOH/g based on solids. The Tg of the acrylic polyolis preferably greater than 25° C., more preferably greater than 40° C.,most preferably between 60 and 110° C.

The hydroxyl-functional film forming polymers, include polyesters,polyacrylates, polyvinyl, polyurethanes, polycarbonates or polyamidesfor non-limiting example, and is preferably an acrylic polyol. Theacrylic polyol is derived from hydroxy-functional acrylic monomers, suchas hydroxy ethyl (meth)acrylate, hydroxy propyl (meth)acrylate, hydroxybutyl (meth)acrylate, other acrylic monomers such as (meth)acrylic acid,methyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl(meth)acrylate, isobornyl (meth)acrylate, trimethyl cyclohexyl(meth)acrylate, and optionally in combination with a vinyl derivativesuch as styrene, and the like, or mixtures thereof, wherein the terms(meth)acrylate and (meth)acrylic acid refer to both methacrylate andacrylate, as well as methacrylic acid and acrylic acid, respectively.The acrylic polyol is prepared by conventional methods, for instance, bythe slow addition of appropriate monomers to a solvent solution of anappropriate polymerization initiator, such as an azo or peroxyinitiator.

In the event that the non-volatile branched mono alcohol is added duringthe preparation of the hydroxyl-functional film forming polymer,preferably during the preparation of the acrylic polyol, the monoalcoholis preferably charged together with a solvent to a reaction vessel priorto the start of the polymerization process.

The weight ratio of the non-volatile branched monoalcohol to solidhydroxyl-functional film forming polymer is preferably 1:99 to 50:50,more preferably 5:95 to 25:75.

Polyisocyanates useful herein as polyisocyanate compounds and inpolyisocyanate components comprise polyisocyanates having two or more,preferably two to four isocyanate groups. Non-limiting examples ofpolyisocyanates useful in the current invention include toluenediisocyanate, methylene bis(4-cyclohexylisocyanate), isophoronediisocyanate and its isocyanurate or adducts, hexamethylene diisocyanateand its isocyanurate, biuret, uretdione, and allophanate, andmeta-tetramethylxylene diisocyanate and the adduct thereof withtrimethylolpropane.

The polyisocyanate compound is used in an amount such that the ratio ofisocyanate groups to the total number of hydroxyl groups in the coatingcomposition is preferably in the range 0.8 to 2.

The solvent can be part of the hydroxl functional component, thepolyisocyanate component and/or it can be a separate reducer. Moreparticularly, in a multi-component system, the reducer may be one of thecomponents. In a multi-component system, comprising a polyisocyanatecomponent, a hydroxl functional component and a third component, thereducer may be the third component.

The coating composition can also comprise catalysts for theisocyanate-hydroxyl reaction, such as dibutyl tin dilaurate, triethylamine, and the like. The coating compositions may also contain pigments.Inorganic as well as organic pigments can be used. The composition canfurther comprise conventional additives, such as stabilizers,surfactants, fillers, UV-absorbers, catalyst blockers, anti-oxidants,pigment dispersants, flow additives, rheology control agents, levellingagents, and solvents. The solvent can be any solvent known in the art.,i.e. aliphatic and/or aromatic hydrocarbons. Examples include Solvesso®100, Exxate 600, toluene, xylene, 4-chloro-benzotrifluoride, butanol,isopropanol, butyl acetate, tert.-butyl acetate, ethyl acetate, methylacetate, methoxy propyl acetate, n-butyl propionate,ethoxyethylpropionate, acetone, methyl isobutyl ketone, methyl isoamylketone, methyl ethyl ketone, ether, ether alcohol, and ether ester, or amixture of any of these.

Preferably, the coating composition comprises less than 550 g/l ofvolatile organic solvent based on the total composition, more preferablyless than 500 g/l, most preferably less than 480 g/l.

The present invention also relates to a multi-component coatingcomposition. Such multi-component coating composition comprises at leasttwo components, i.e. a hydroxyl-functional component and apolyisocyanate component. Preferably, the multi-component coatingcomposition comprises three components having a third component, i.e. areducer, comprising solvents to provide a coating composition with asprayable viscosity.

The coating composition of the present invention may be applied to anysubstrate. The substrate may be, for example, metal, plastic, wood,glass, ceramic, or another coating layer. The other coating layer may becomprised of the coating composition of the current invention or it maybe a different coating composition. The coating compositions of thecurrent invention show particular utility as clearcoats, basecoats,pigmented topcoats, primers, and fillers. The coating compositions canbe applied by conventional means such as by spray gun, brush, or roller,spraying being preferred. Curing temperatures are preferably between 0and 80° C., and more preferably between 20 and 60° C. The compositionsare particularly suitable in the preparation of coated metal substrates,such as in the refinish industry, in particular the body shop, to repairautomobiles and transportation vehicles and in finishing largetransportation vehicles such as trains, trucks, buses, and airplanes.

Preferred is the use of the coating composition of the present inventionas clearcoat. Clearcoats are required to be highly transparent and mustadhere well to the basecoat layer. It is further required that theclearcoat does not change the aesthetic aspect of the basecoat bystrike-in, i.e. discoloration of the basecoat due to solvents present inthe clearcoat composition, or by yellowing of the clearcoat upon outdoorexposure. A clearcoat based on the coating composition of the presentinvention does not have these drawbacks.

Accordingly, the present invention also relates to a process for thepreparation of a multilayer coating comprising the steps of applying abasecoat composition on an optionally coated substrate, optionallycuring the basecoat, applying on top of the basecoat a clearcoatcomposition according to the present invention, and curing themultilayer coating.

In the case of the coating composition being a clearcoat, the basecoatmay be a conventional basecoat known in the coating art. Examples aresolvent borne basecoats, e.g. Autobase® ex Akzo Nobel Coatings and waterborne basecoats, e.g., Autowave® ex Akzo Nobel Coatings. Furthermore,the basecoat may comprise pigments (color pigments, metallics and/orpearls), wax, solvents, flow additives, neutralizing agent, anddefoamers. Also high-solid basecoats can be used. These are, forinstance, based on polyols, imines, and isocyanates. The clearcoatcomposition is then applied to the surface of a basecoat and then cured.An intermediate curing step for the basecoat may be introduced.

The invention is further illustrated by the following specific butnon-limiting examples.

EXAMPLES Example 1

Acrylic Polyol 1

Acrylic Polyol 1 was produced by charging 700 g n-butyl propionate to a5-liter, 4-neck round bottom flask equipped with a stirrer, condenser,heating mantle, thermocouple with thermowatch, nitrogen and additioninlets. The solvent was heated to the reflux temperature, 145-150° C.under a nitrogen blanket.

When the temperature reached and stabilized at reflux, 145-150° C., thefollowing mixture was added supersurface to the flask over 180 minutes:600 g styrene, 800 g tert-butyl methacrylate, 200 g n-butylmethacrylate, 400 g 2-hydroxyethyl methacrylate, and 79 g tertbutylperoxy-3,5,5-trimethylhexanoate. During the addition of this mixture,the reaction temperature was kept at reflux and under nitrogen blanket.After completion of the addition, the addition lines were initiallyrinsed with 50 g of n-butyl acetate followed by a chaser additionmixture 50 g of n-butyl acetate and 1.0 g tert-butylperoxy-3,5,5-trimethylhexanoate. The reaction temperature was held atreflux for an additional hour. Finally, 320 g n-butyl acetate was addedas a letdown solvent.

The resulting solution of high solid Acrylic Polyol 1 had a non-volatilecontent of 64.3%, a Brookfield viscosity of 3,800 cps (25° C., Spindle 4and 20 RPM), and a hydroxyl number of 86.3 (mg KOH/g on solids). Themolecular weight of the polymer was measured using Waters' Associatesgel permeation chromatography (GPC) and Phenomenex polystyrenestandards. The high solid Acrylic Polyol 1 had an Mn of 3,020, an Mw of8,134, a degree of dispersion, D, of 2.69 and a theoretical Tg of 87°.

Hydroxyl-Functional Component 1

Hydroxyl-functional Component 1 was produced by mixing

-   74.3 g Acrylic Polyol 1 produced above,-   4.2 g Guerbet alcohol having 18 carbon atoms (ISOFOL® 18T from    CONDEA Chemie GmbH, Hamburg, Germany),-   8.0 g butyl acetate,-   8.8 g acetone,-   0.1 g dibutyl tin dilaurate (10% in butyl acetate),-   1.7 g flow additive (Byk 310, ex Byk Chemie, 10% in xylene),-   1.4 g UV stabilizer (Tinuvin 292, ex Ciba), and-   1.4 g UV stabilizer (Tinuvin 1130, ex Ciba).    Polyisocyanate Component 1

The following were mixed to produce Polyisocyanate Component 1:

-   55 g isocyanurate of hexane diisocyanate (90% in butyl acetate,    Desmodur N3390, ex Bayer),-   16.2 g xylene,-   16.8 g methoxypropyl acetate, and-   11.4 g butyl acetate.    Reducer 1

The following were mixed to produce Reducer 1:

-   22.8 g acetone,-   13.5 g methoxypropyl acetate, and-   63.7 g Exxate 600.    Coating Composition 1 Formation and Application

The Hydroxyl-functional Component 1, the Polyisocyanate Component 1, andthe Reducer 1 were mixed in a volume ratio 100:50:30 to produce a cleartop coat version of the coating composition according to the presentinvention. In a first step, the Polyisocyanate Component 1 and theReducer 1 were mixed together. In a second step, the Hydroxy-functionalComponent 1 was added. The clear top coat had a VOC of 4.0 lb/galexcluding acetone. The crosslink ratio NCO:OH was 1.4.

To evaluate the instant invention, test panels were primed withColorbuild® sealer (ex Akzo Nobel Coatings), then sprayed with Autobase®basecoat (ex Akzo Nobel Coatings). The clear top coat prepared above wassprayed on the thus prepared panels. Properties of the clear top coatingcomposition and the resulting coating are reported in Table 1.

Comparative Examples A and B

To demonstrate the improved flow and appearance resulting from theinstant invention, Comparative Example A is a repetition of Example 1except the non-volatile branched aliphatic monoalcohol is omitted; thatis, no Guerbet alcohol is present. In Comparative Example B, thenon-volatile branched aliphatic monoalcohol is replaced by Desmophen670, an 80% polyester polyol solution in butyl acetate from Bayer.

Comparative Example A

Hydroxyl-Functional Component A

Hydroxyl-functional Component A was produced by mixing

-   80.8 g Acrylic Polyol 1 produced above,-   5.7 g butyl acetate,-   8.8 g acetone,-   0.1 g dibutyl tin dilaurate (10% in butyl acetate),-   1.7 g flow additive (10% Byk 310, ex Byk Chemie in xylene)-   1.4 g UV stabilizer (Tinuvin 292, ex Ciba), and-   1.4 g UV stabilizer (Tinuvin 1130, ex Ciba).    Coating Composition A and Application

A coating composition A was prepared and applied identically to that ofExample 1 except that the Hydroxyl-functional Component A was used. TheVOC was 4.0 lb/gal excluding acetone. The crosslink ratio was 1.4.Properties of the coating composition of Comparative Example A and theresulting coating are reported in Table 1.

Comparative Example B

Hydroxyl-Functional Component B

Hydroxyl-functional Component B was produced by mixing

-   74.3 g Acrylic Polyol 1 produced above (70% in methyl amyl ketone),-   5.3 g Desmophen 670 (80% in butyl acetate),-   6.9 g butyl acetate,-   8.8 g acetone,-   0.1 g dibutyl tin dilaurate (10% in butyl acetate),-   1.7 g flow additive (10% Byk 310, Byk Chemie in xylene)-   1.4 g UV stabilizer (Tinuvin 292, ex Ciba), and-   1.4 g UV stabilizer (Tinuvin 1130, ex Ciba).    Coating Composition B and Application

A coating composition B was prepared and applied identically to that ofExample 1 except that the Hydroxyl-functional Component B was used. TheVOC was 4.0 lb/gal excluding acetone. The crosslink ratio was 1.4.Properties of the coating composition of Comparative Example B arereported in Table 1.

TABLE 1 Ex- Comp. Comp. Property Method (unit) ample 1 Example A ExampleB Viscosity @ DC4 (sec) 13.9 15.7 15.1 70° F. Viscosity after DC4 (sec)23.2 20.3 21.2 2 hrs. Free to Manual (min) 36 29 35 handle @ 60° C.Hardness 1 day Persoz (sec) 62 59 52 Hardness 7 day Persoz (sec) 151 159124 DOI (7 days) 85 75 75 Appearance Visual 8.5 6.5 6.7 (3 persons) Sshort wave Wave Scan 4.9 10.3 10.3 tension (Byk) L long wave Wave Scan31.1 33.2 34.1 tension (Byk)

As demonstrated by the data reported in Table 1, the use of thenon-volatile branched monoalcohol provides surprising flow andappearance characteristics in the coating composition of the presentinvention while maintaining other desirable properties.

Example 2

Acrylic Polyol 2

Acrylic Polyol 2 was produced by charging 200 g n-butyl propionate and500 g of Guerbet Alcohol, i.e. Isofol® 18T, to a 5-liter, 4-neck roundbottom flask equipped with a stirrer, condenser, heating mantle,thermocouple with thermowatch, nitrogen and addition inlets. The mixturewas heated to 150° C. under a nitrogen blanket.

When the temperature of 150° C. was reached, the following mixture wasadded supersurface to the flask over 180 minutes: 1000 g styrene, 200 gtert-butyl methacrylate, 400 g n-butyl methacrylate, 400 g2-hydroxyethyl methacrylate, and 98 g tert-butyl peroxy3,5,5-trimethylhexanoate. During the addition of this mixture, thereaction temperature was kept at reflux and under nitrogen blanket.After completion of the addition, the addition lines were initiallyrinsed with 50 g of tert-butyl acetate followed by a chaser additionmixture 50 g of tert-butyl acetate and 1.0 g tert-butylperoxy-3,5,5-trimethylhexanoate. The reaction temperature was kept at150° C. for an additional hour. Finally, 814 g tert-butyl acetate wasadded as a letdown solvent.

The resulting solution of high solid Acrylic Polyol 2 had a non-volatilecontent of 70.1%, a Brookfield viscosity of 1,800 cps at 65% (reducedwith tert-butyl acetate 25° C., Spindle 4 and 20 RPM), and a hydroxylnumber of 112.7 (mg KOH/g on solids). The molecular weight of thepolymer was measured using Waters' Associates gel permeationchromatography (GPC) and Phenomenex polystyrene standards. The highsolid Acrylic Polyol 2 had an Mn of 3,750, an Mw of 8,430, a degree ofdispersion, D, of 2.2.

Hydroxyl-Functional Component 2

Hydroxyl-functional Component 2 was produced by mixing

-   67.9 g Acrylic Polyol 2 produced above,-   10.0 g ethoxyethylpropionate,-   13.8 g acetone,-   0.1 g dibutyl tin dilaurate (10% in butyl acetate),-   1.7 g flow additive (10% Byk 310, Byk Chemie in xylene)-   1.4 g UV stabilizer (Tinuvin 292, ex Ciba), and-   1.4 g UV stabilizer (Tinuvin 1130, ex Ciba).    Hydroxyl-Functional Component 3

Hydroxyl-functional Component 3 was produced by mixing

-   68.8 g Acrylic Polyol 1 produced above,-   12.5 g Guerbet alcohol, i.e. Isofol® 18T,-   3.5 g ethoxyethylpropionate,-   12 g acetone,-   0.2 g dibutyl tin dilaurate (10% in butyl acetate),-   0.4 g flow additive (10% Byk 310, Byk Chemie in xylene)-   1.3 g UV stabilizer (Tinuvin 292, ex Ciba), and-   1.3 g UV stabilizer (Tinuvin 1130, ex Ciba).    Polyisocyanate Component 2

The following were mixed to produce a hardener:

-   70 g isocyanurate of hexane diisocyanate (Desmodur N3600, Bayer),-   30 g tert-butyl acetate.    Polyisocyanate Component 3-   65 g isocyanurate of hexane diisocyanate (Desmodur N3600, Bayer),-   35 g 4-chloro-benzotrifluoride.    Coating Compositions 2 and 3 Formation and Application

The Hydroxyl-functional Component 2, the Polyisocyanate Component 2, anda reducer were mixed in a volume ratio 100:50:30 to produce a clearcoatversion 2 of the coating composition according to the present invention.Tert-butylacetate was used as reducer for coating composition 2.Clearcoat version 3 was prepared in the same way except that4-chloro-benzotrifluoride was used as a reducer. The clearcoats had aVOC of 2.0 lb/gal excluding exempt solvents at a spray viscosity of13-14 seconds DC4.

To evaluate the instant invention, test panels were primed withColorbuild® sealer (ex Akzo Nobel Coatings), then sprayed with Autobase®basecoat (ex Akzo Nobel Coatings). The clearcoat prepared above wassprayed on the thus prepared panels. Both clearcoats showed excellentflow and appearance.

1. A coating composition comprising a polyisocyanate compound, ahydroxyl-functional film-forming polymer, and a branched non-volatilemonoalcohol.
 2. The coating composition of claim 1 further comprising areducer.
 3. The coating composition of claim 1 wherein thehydroxy-functional film-forming polymer is an acrylic polyol.
 4. Thecoating composition of claim 1 wherein the monoalcohol has at least anaverage of 12 carbons.
 5. The coating composition of claim 1 wherein themonoalcohol has at least an average of 16 carbons.
 6. The coatingcomposition of claim 1 wherein the monoalcohol is a Guerbet alcohol. 7.The coating composition of claim 1 wherein the weight ratio of themonoalcohol to solid acrylic polyol is 1:99 to 50:50.
 8. The coatingcomposition of claim 7 wherein the weight ratio is 5:95 to 25:75.
 9. Thecoating composition of claim 1 wherein the hydroxyl-functionalfilm-forming polymer has a Tg of higher than 25° C.
 10. The coatingcomposition of claim 9 wherein the Tg is higher than 40° C.
 11. Thecoating composition of claim 1 wherein the branched non-volatilemonoalcohol is aliphatic.
 12. The coating composition of claim 1 whereinthe hydroxyl-functional film-forming polymer is prepared in the presenceof the branched non-volatile monoalcohol.
 13. A multi-component coatingcomposition comprising a polyisocyanate component and ahydroxyl-functional component, wherein the hydroxyl-functionalcomponent, in addition to the hydroxyl-functional film forming polymeralso comprises the branched non-volatile monoalcohol.
 14. Amulti-component coating composition according to claim 13 furthercomprising a third component wherein the third component is a reducer.15. The multi-component coating composition of claim 13 wherein thehydroxy-functional film-forming polymer is an acrylic polyol.
 16. Themulti-component coating composition of claim 13 wherein the monoalcoholhas at least an average of 12 carbons.
 17. The multi-component coatingcomposition of claim 13 wherein the monoalcohol has at least an averageof 16 carbons.
 18. The multi-component coating composition of claim 13wherein the monoalcohol is a Guerbet alcohol.
 19. The multi-componentcoating composition of claim 13 wherein weight ratio of the monoalcoholto solid acrylic polyol is 1:99 to 50:50.
 20. The multi-componentcoating composition of claim 19 wherein the weight ratio is 5:95 to25:75.
 21. The multi-component coating composition of claim 13 whereinthe hydroxyl-functional film-forming polymer has a Tg of higher than 25°C.
 22. The multi-component coating composition of claim 21 wherein theTg is higher than 40° C.
 23. The multi-component coating composition ofclaim 13 wherein the branched nonvolatile monoalcohol is aliphatic. 24.The multi-component coating composition of claim 13 wherein thehydroxyl-functional film-forming polymer is prepared in the presence ofthe branched non-volatile monoalcohol.
 25. A method of refinishing acar, the method comprising applying a coating composition according toclaim 1 to the car.
 26. A method of refinishing a car, the methodcomprising applying a multi-component coating composition according toclaim 13 to the car.
 27. A clearcoat composition comprising a coatingcomposition according to claim
 1. 28. A clearcoat composition comprisinga coating composition according to claim
 13. 29. Process for thepreparation of a multi-layer coating comprising (a) applying a basecoatcomposition to a substrate, (b) applying on top of the basecoat aclearcoat composition according to claim 1, and curing the multi-layercoating.
 30. Process for the preparation of a multi-layer coatingcomprising (a) applying a basecoat composition to an optionally coatedsubstrate, (b) optionally curing the basecoat, (c) applying on top ofthe basecoat a clearcoat composition according to claim 14, and curingthe multi-layer coating.
 31. A process according to claim 29 wherein thesubstrate is coated prior to applying the base coat of step (a).
 32. Aprocess according to claim 30 further comprising the step of curing thebasecoat applied in step (a) prior to applying the clearcoat in step(c).